Passenger seat, passenger seat leg module and method

ABSTRACT

A passenger seat which includes a seat bottom chassis assembled from a plurality of leg modules attached to fixed, spaced-apart attachment points on a supporting surface, and a plurality of beam elements for being carried by the leg modules. A plurality of clamp joints are positioned on a first side of the leg modules in a first laterally-offset relation thereto in a first spaced-apart relation to the attachment points of the supporting surface and for receiving the plurality of beam elements for defining a ladder frame assembly having a first specified width and seat spacing. The plurality of clamp joints are removable from the first side of the leg modules can positioned on a second, opposite side of the leg modules in a second laterally-offset relation for defining a ladder frame assembly having a second specified width and seat spacing while the plurality of leg modules maintain the same position relative to each other and thus to the fixed, spaced apart attachment points whereby the location of the seats may be altered while using the same beam elements.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

[0001] This invention relates to a passenger seat such as used on anaircraft, a leg module for a passenger seat, and a method of mounting apassenger seat to attachment points on a supporting surface, such as thedeck of an aircraft fuselage.

[0002] Passenger seat frames are constructed from modular sets ofcomponents designed to be lightweight and conformable to variousaircraft cabin conditions. The lower seat chassis is constructed of legmodules. A leg module includes a front leg, a diagonal leg tie and aback leg.

[0003] The upper seat chassis is constructed of section assemblymodules. The leg modules and section assembly modules are assembled byattachment to lateral tubular beam elements to form a ladder frameassembly. A seat bottom and a seat back are mounted to the ladder frameassembly to form the passenger seat. The seat back typically includes arecline unit which allows the seat back to be moved between relativelyupright and reclined positions for passenger comfort and ingress/egressrequirements. The location of the section assembly modules is controlledby the aircraft fuselage lines and statutory aisle requirements. Thesection modules carry pivots for both sides of the seat back and anadditional pivot on one side to carry the reaction loads of the reclineunit of the seat back.

[0004] The location of the leg modules is controlled by the position ofthe aircraft floor tracks which extend along the length of the fuselage,and to which the seats are affixed by track fittings carried on thebottom of the leg module. Presently, aircraft passenger seats requiredthree different leg module designs to accommodate the seat spacingrequirements while fitting into the tract fittings.

[0005] The present invention permits a single leg module to be used forall seat spacing requirements.

SUMMARY OF THE INVENTION

[0006] Therefore, it is an object of the invention to provide apassenger seat which includes a leg module that can be used in differentspacing configurations.

[0007] It is another object of the invention to provide a passenger seatwhich includes a detachable joint clamp that permits a single leg moduleto be used in different spacing configurations.

[0008] It is another object of the invention to provide a passenger seatleg module that can be used in different spacing configurations.

[0009] It is another object of the invention to provide a passenger seatleg module which includes a detachable joint clamp that permits a singleleg module to be used in different spacing configurations.

[0010] It is another object of the invention to provide a method ofconstructing a passenger seat using a single type of leg module.

[0011] These and other objects of the present invention are achieved inthe preferred embodiments disclosed below by providing a passenger seatwhich includes a seat bottom chassis assembled from a plurality of legmodules, the leg modules for being attached to fixed, spaced-apartattachment points on a supporting surface, and a plurality of beamelements for being carried by the leg modules. A plurality of clampjoints are positioned on a first side of the leg modules in a firstlaterally-offset relation thereto in a first spaced-apart relation tothe attachment points of the supporting surface and for receiving theplurality of beam elements for defining a ladder frame assembly having afirst specified width and seat spacing. The plurality of clamp jointsare removable from the first side of the leg modules can positioned on asecond, opposite side of the leg modules in a second laterally-offsetrelation thereto for defining a ladder frame assembly having a secondspecified width and seat spacing while the plurality of leg modulesmaintain the same position relative to each other and thus to the fixed,spaced apart attachment points whereby the location of the seats may bealtered while using the same beam elements.

[0012] According to one preferred embodiment of the invention, thepassenger seat includes a seat back recline assembly, comprising aplurality of seat section assembly modules carried by the leg modules,and a seat back unit pivotally-mounted between two of the sectionassembly modules for permitting the angle of the seat back relative tothe seat bottom chassis to be varied as desired by the passenger, arecline unit for controlling movement of the seat back and locking theseat back in a desired recline position.

[0013] According to another preferred embodiment of the invention, eachof the leg modules comprises a rear foot block and floor tie assembly, afront leg, and a diagonal leg tie connecting the rear foot block and thefront leg. A first one of the plurality of clamp joints is connected inlaterally-offset relation to one side of the diagonal leg tieintermediate the rear foot block and the front leg, and a second one ofthe plurality of clamp joints is connected in laterally-offset relationto one side of the front leg.

[0014] According to yet another preferred embodiment of the invention,the clamp joint comprises an attachment element for being attached tothe leg module and an annular collar element for receiving a beamtherethrough.

[0015] According to yet another preferred embodiment of the invention,the clamp joint attachment element includes holes therein for receivingattachment bolts therethrough and through mating holes in the legmodule.

[0016] According to yet another preferred embodiment of the invention,the clamp joint collar includes an axially-extending split therein forallowing the collar to be spread sufficiently to receive the beamtherethrough, and a threaded fastener adjustably connecting the collaron opposite sides of the split for permitting the collar to be tightenedfog locking the beam in place within the collar in a predeterminedposition and loosened for permitting the beam to the removed from orshifted axially within the collar.

[0017] According to yet another preferred embodiment of the invention,the passenger seat includes first and second spaced-apart leg modules.The clamp joints of the first leg module are positioned on a left sidethereof; and the clamp joints of the second leg module are positioned ona right side thereof.

[0018] According to yet another preferred embodiment of the invention,the passenger seat includes first and second spaced-apart leg moduleswherein the clamp joints of the first leg module are positioned on aright side thereof, and the clamp joints of the second leg module arepositioned on a right side thereof.

[0019] According to yet another preferred embodiment of the invention,the passenger seat includes first and second spaced-apart leg moduleswherein the clamp joints of the first leg module are positioned on aleft side thereof, the clamp joints of the second leg module arepositioned on a left side thereof.

[0020] According to yet another preferred embodiment of the invention, apassenger seat leg module is provided, and comprises a rearfoot blockand floor tie assembly, a front leg, a diagonal leg tie connecting therear foot block and the front leg, and a first clamp joint for beingconnected in laterally-offset relation to a selected one of a left orright side of the diagonal leg tie intermediate the rear foot block andthe front leg for receiving a beam therethrough. A second clamp joint isprovided for being connected in laterally-offset relation to a selectedone of a left or right side of the front leg for receiving a beamtherethrough.

[0021] An embodiment of the method of mounting a passenger seat toattachment points on a supporting surface comprises the steps ofproviding a seat bottom chassis including a plurality of leg modules,the leg modules for being attached to fixed, spaced-apart attachmentpoints on a supporting surface, a plurality of beam elements carried bythe leg modules, and a plurality of clamp joints. A clamp joint isattached to each of the plurality of leg modules for clamping theplurality of leg modules together in spaced-apart relation to eachother, each the clamp joint having a hole therethrough for receiving abeam element. The plurality of beam elements extend through an openingin the clamp joints for defining a ladder frame assembly having apredetermined width and seat spacing.

[0022] According to yet another preferred embodiment of the invention,the method includes the steps of removing the beams from the clampjoints, removing the clamp joints from one side of the leg modules andattaching the clamp joints to an opposite side of the leg modules, andextending the plurality of beam elements through respective openings inthe clamp joints to define a ladder frame assembly having a secondspecified width and seat spacing.

[0023] According to yet another preferred embodiment of the invention,the method includes the steps of positioning the clamp joints of a firstleg module on a left side thereof, and positioning the clamp joints of asecond leg module on a right side thereof.

[0024] According to yet another preferred embodiment of the invention,the method includes the steps of positioning the clamp joints of a firstleg module on a right side thereof, and positioning the clamp joints ofa second leg module on a right side thereof.

[0025] According to yet another preferred embodiment of the invention,the method includes the steps of positioning the clamp joints of a firstleg module on a left side thereof, and positioning the clamp joints of asecond leg module on a left side thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE Seat AssemblyOverview

[0026] Referring now specifically to the drawings, an aircraft passengerseat set according to the present invention is illustrated in FIGS. 1, 2and 3 and shown generally at reference numeral 10. In the particularembodiment shown in FIGS. 1, 2 and 3, the seat set 10 is comprised ofthree adjacent seats, an aisle seat 11, a center seat 12 and a windowseat 13. The seat set 10 is supported on a pair of leg modules 14 and15, and includes a baggage guard rail 16. The seats 11, 12 and 13 areprovided with arm rests 18, 19, 20 and 21. The seats 11, 12 and 13include seat bottoms 22, 23 and 24, respectively, and seat backs 25, 26and 27, respectively.

[0027] The internal structure of the seat set is shown in FIG. 4, withvarious parts eliminated for clarity. As is shown, the seat set 10 issupported on and thus shares the two leg modules 14 and 15. The legmodules 14 and 15 carry a set of four laterally-extending beam elements35, 36, 37 and 38 on which are mounted four section assembly modules 40,41, 42 and 43. The leg modules 14, 15; beam elements 35, 36, 37 and 38;and the section assembly modules 40, 41, 42 and 43 tie together thecomponents in a manner necessary to form a seat set 10 havingsignificant structural integrity within passenger comfort, fuselage sizeand government regulation requirements. The underlying structure definedby leg modules 14, 15; beam elements 35, 36, 37 and 38; and the sectionassembly modules 40, 41, 42 and 43 is referred to as a “ladder frameassembly” and is indicated at reference numeral 50 in FIGS. 4 and 5. Theladder frame assembly 50 carries seat back pans 26A, 27A, see FIG. 4,and seat back pan 25A, see FIG. 5.

[0028] Of course, the seats according to the present invention can beintegrated together to form seat sets of different lengths, spacings,and numbers of seats. Whether one, two, three or more seats, each seatset 10 will include at least two leg modules, such as leg modules 14 and15. Thus, when a seat is referred to as having a pair or a plurality ofleg modules, it is understood that at least two leg modules arerequired, but that the two leg modules may not necessarily be onopposing sides of any particular seat. For example, in FIGS. 1-5, threeseats 11, 12 and 13 are each supported on two leg modules 14, 15. Thus,seat 11 is supported on two leg modules 14, 15, just as are seats 12 and13, and whether the seat set 10 is considered a “seat” or the threeseats 11, 12 and 13 are considered “seats”, in either case they aresupported by a plurality of legs.

Low Profile Seat Back Recline Locking Assembly

[0029] Referring now to FIGS. 6 and 7, a low profile seat back reclinelocking assembly is shown. A hydraulic cylinder 60 interconnects thesection assembly module 41 and the seat back pan 25A. A control button,not shown, on the arm rest 19 can be depressed by the seat occupant tovary the recline angle of the seat back 26 relative to the seat bottom23. The control button is connected to a control cable, not shown, whichconnects to the actuator 61 residing on top of the cylinder 60. When thecontrol button is depressed, the actuator 61 unlocks the cylinder 60.Backward pressure on the seat back pan 25A allows the seat back pan 25Ato recline. Release of back pressure on the seat back pan 25A by theseat occupant allows the seat back pan 25A to move forwardly to a moreupright position. Release of the control button locks the seat back 25in the current position.

[0030] The cylinder 60 is mounted for pivotal movement to the sectionassembly module by an offset pivot shaft 62 by a lower cylinder pivotbushing 63 and to the seat back pan 25A by a pair of upper cylinderpivot bushings 64, 65 between which fits a pivot bushing, not shown,residing behind the lower extent of the seat back pan 25A. The uppercylinder pivot bushings 64, 65 are locked in place by a lock pin 68,designed to be removable without tools.

[0031] The pivot shaft 62 is locked to the section assembly module 41 bya pear-shaped spacer collar 70 having a bore 71 into which the pivotshaft 62 extends. The spacer collar 70 is connected to the sectionassembly module 41 by a screw 72 which is threaded into a matinglythreaded screw hole 73 in the small end of the spacer collar 70.

[0032] Note that the spacer collar 70 fits against a stepped surfaceportion of the section assembly module 41. The stepped surface portionincludes a first portion 75 which is flush with the surrounding surfaceof the section assembly module 41 and a second portion 76 which isrecessed below the surrounding surface of the section assembly module41. The pivot shaft fits into a bore 78 in the section assembly module41, and the screw 72 threads into a matingly threaded hole 79.

[0033] Thus, in order to lock the pivot shaft 62 against movementrelative to the section assembly module 41, the screw 72 is tightened tothe point where the smaller end of the spacer collar 70 is drawninwardly into the recessed portion 76 of the section assembly moduleunderlying the spacer collar 70. This tilting movement creates amisalignment of the axis of the spacer collar 70 relative to the axis ofthe pivot shaft 62, thus locking the pivot shaft 62 against both axialand rotational movement relative to the section assembly module 41. Asthe seat back pan 25A moves, the cylinder 60 pivots about the pivotshaft 62.

[0034] Similarly, the seat back pivot shaft 80 is mounted in a pivotbushing 81 on the seat back pan 25A and in a bore 82 in the sectionassembly module 41. The seat back pivot shaft 80 is locked to thesection assembly module 41 by a spacer collar 84. In the same manner asdescribed above, the spacer collar 84 sits over a stepped portion of thesurface of the section assembly module 41, so that when the screw 85 istightened, the small end of the spacer collar 84 is misaligned, lockingthe seat back pivot shaft 80 in a fixed position relative to the sectionassembly module 41.

[0035] The spacer collars 70 and 84 are preferably manufactured fromextrusion and thus can be easily made in any desired thickness.

[0036] The seat back pivot shaft 80 is attached to the pivot bushing bya fastener 87. A screw 88 is threaded into the fastener 87, whichincludes a misaligned portion 89. As the screw 88 is tightened, themisaligned portion 89 becomes progressively more misaligned, securingthe seat back pivot shaft 80 to the pivot bushing 81 of the seat backpan 25A.

[0037] As is shown in FIG. 7, beam elements 35 and 36 carry the sectionassembly module 41, also as shown in FIG. 4, together with the beamelements 37 and 38.

[0038] The cylinder 60 is very compact—approximately 5 inches betweenattachment points, and has a ½ inch stoke. By locating the actuator 61astride the cylinder 60, the overall length is further reduced. Thisshorter length allows the cylinder 60 to be located in a nearly verticalposition to one side of and behind the seat occupant. The seat bottompan therefore has a clean appearance without local protuberances. As aresult, the bottom cushion can be thinner, less complex, morecomfortable and lighter than those in current use. Recline of the seatback 26 is unaffected, and is completely transparent to the seatoccupant.

Seat Frame Construction

[0039] Referring now to FIG. 8, leg module 14 is described in furtherdetail. Leg module 14 includes a rear floor track fitting 90 by whichthe seat set 10 is attached to a track extending along the fuselage deckfrom front to rear, a floor tie assembly 91, a front leg 92, a fronttrack fitting 93, and a diagonal leg tie 94. A pair of joint clamps 96,98 are provided and comprise an annular collar element 96A, 98A,respectively, which receive the beam elements 37, 36, and attachmentelements 96B, 98B, respectively, by which the joint clamps 96, 98 areattached to the leg module 14.

[0040] The joint clamps 96, 98 are secured by screws 99 to the top ofthe front leg 92 and the diagonal leg tie 94, respectively. The jointclamps 96, 98 include axially-extending splits 96C, 98C, respectively,which permit the collar elements 96B, 98B to be spread sufficiently topermit insertion of the beam elements 37,36. Screws 100 permit thecollar elements 96B, 98B to be tightened for locking the beam elements37, 36 in place in a predetermined position, and loosened for permittingthe beam elements 37, 36 to the removed from or shifted axially withinthe collar elements 96B, 98B.

[0041] As shown in FIG. 4, the section assembly modules 41 and 42 aremounted to the beam elements 37, 36 in an offset position relative tothe joint clamps 96, 98 and form the ladder frame assembly 50.

[0042] Referring now to FIGS. 9, 10 and 11, the manner in which thejoint clamps 96, 98 may be used to vary seat spacing is illustrated. Asnoted above, spacing between parallel sets of floor tracks is generallyfixed, so that the need to have seats with varying spacing in prior artconstructions has been accommodated by having differently-constructedleg modules with various offsets to the left or right of the centerlineof the leg module. By using the joint clamps 96, 98, seat spacing isvaried using the same components, avoiding the need to have a number ofdifferently-constructed leg modules and components. For example, in FIG.9 the joint clamps 96, 98 are positioned on the right side of the legmodules 14, 15. The location of the collars 96A, 98A permit the sectionassembly modules 41, 42 to be positioned in vertical alignment with orto the left of the leg modules 14, 15.

[0043] In FIG. 10 the joint clamps 96, 98 are positioned on the leftside of the leg modules 14, 15, permitting the section assembly modules41, 42 to be positioned in vertical alignment with or to the right ofthe leg modules 14, 15.

[0044] In FIG. 11 the joint clamps 96, 98 are positioned inboard of theleg modules 14, 15, permitting the section assembly modules 41, 42 to bepositioned in vertical alignment with or outboard of the leg modules 14,15. Even though not shown, it is also apparent that the joint clamps canbe both positioned outboard of the leg modules 14, 15, permitting thesection assembly modules 41, 42 to be positioned in vertical alignmentwith or inboard of the leg modules 14, 15. The attachments are notpermanent, so that modifications to the seat spacing requirements can bequickly and easily accomplished.

Seat Back Breakover Assembly

[0045] Referring now to FIGS. 12, 13, 13A-C and 14, a breakover assembly100 for a passenger seat such as the passenger seat 11 is shown. Thebreakover assembly 100 is intended to normally prevent the seat back 25,see FIG. 5, from pivoting forward past an upright position towards theseat bottom 22, while allowing this movement if struck with asufficiently hard forwardly-directed force, such as might occur if hitfrom the rear by an occupant seated directly behind the seat. Thepurpose of the breakover assembly 100 is to prevent damage to the seat11 resulting from a severe rear impact and to at least reduce injury toan occupant thrown against the rear of the seat back by allowing theseat back to move forwardly in a controlled manner.

[0046] In general, this is effected by utilizing a bent steel wire toresist impact up to a certain predetermined load, and then absorb theenergy by forcing the bend in the wire rearwardly relative to the wire,forwardly relative to the seat, and giving off excess energy in the formof heat.

[0047] Specifically, a bent steel wire 101 as is shown in the simplifiedview of FIG. 12 is captured by a retainer bracket 102. The steel wire isa 0.235 inch 1018 grade wire. An energy-absorbing roller 103 and bushing103A are positioned inside the bend of the steel wire 101. The roller103 is captured in holes 105A and 106A in back supports 105, 106,respectively and thus must move in unison with the back supports 105,106. The bushing 103A resides in lateral alignment with the steel wire101 inside the bend.

[0048] A shear pin 104 carrying a shear bushing 104A thereon is capturedin holes 105B and 106B in back supports 105, 105, respectively. Theshear bushing 104A is captured in an annular recess 107 in a quadrantmember 108. The steel wire 101 fits around the back side 108 of thequadrant member 108, with the forward portion of the wire 101 positionedin the elongate slot 109. The forward portion of the wire 101 isretained in slot 109 by an enlarged head 101A which fits within anannular recess at the end of the slot 109. See FIG. 13.

[0049] The entire seat back 25 pivots on the pivot bushing 112 on whichthe back supports 105, 106 and quadrant 108 are positioned. See FIG. 14.Other components shown are illustrated and described above.

[0050] In operation, an abnormal force, for example, the impact of apassenger on the rear of the seat during a 16 g event will cause theseat back 25 to move forward while the quadrant 108 remains stationary.The shear bushing 104A fits snugly within the recess 107 and thusquickly breaks. The shear bushing 104A is designed to break upon impactof between 180-220 pounds on the top of the seat back 25. See FIGS. 13A,13B. The width of the shear bushing 104A can be varied, and in doing sothe amount of force required to break the shear bushing 104A can bevaried. The wire 101 is protected from any load until the shear bushing104A breaks.

[0051] As the shear bushing 104A breaks, the seat back 25 continuesforward, bringing the bushing 103A up against the back of the inside ofthe bend in the wire 101. As the seat back 25 continues forward, thebushing 103A continues forward, and the wire 101 is pulled around thebushing 103A, moving the position of the bend. See FIG. 13C. Energy isabsorbed in two ways, movement of the position of the bend along thelength of the wire 101 and heat released as the wire 101 thus bent.

[0052] Wire 101 is designed to begin movement at 150 pounds of force,and permits the seat back 25 to move through a maximum arc of 70degrees. The combined use of the sacrificial bushing 104A and the wire101 controls the movement of the seat back 25 in such a manner thatsurvivability of the passenger is improved at an impact force as low as1G. The seat back 25 can be returned to its normal position by pushingit rearward using less than a 35 lbs force.

[0053] When the seat back must be moved forward for maintenance orcleaning, the lock pin 68 may be removed, disconnecting the hydraulicseat recline cylinder 60 from the retainer bracket 102 and the seat back25. In this configuration the seat back 25 may be moved forward to thebreakover position without interfering with the quadrant 108.

Meal Tray Assembly—Preferred Embodiment

[0054] Referring now to FIG. 15, a meal tray assembly 120 according apreferred embodiment of the invention is illustrated. The meal trayassembly includes a pair of laterally spaced-apart latch plates 121, 122connected to the back surface of the seat back pan 25A of passenger seat11 directly above a meal tray stowage position. The latch plates 121,122 include inwardly-facing pin retention recesses 121A, 122A,respectively. The dress cover of the seat back 25 is around the latchplates 121, 122 so as not to interfere with the latch plates 121, 122when the dress cover is removed for cleaning or replacement.

[0055] A cross-member 124 is positioned laterally across the surface ofthe seat back pan 25A and releasably locked to the seat back pan 25A bya pair of locking pins 125, 126, which are mounted in recesses, notshown, in the back side of the cross-member 124 by a pair of coverplates 128, 129. The cross-member 124 is positioned over the dresscover. The locking pins 125, 126 are biased in the locked position bysprings 131, 132. When the cross-member 124 is placed against the backof the seat back pan 25A and over the latch plates 121, 122, the lockingpins 125, 126 extend into the retention recesses 121A, 122A and lock thecross-member 124 to the back of the seat back pan 25A.

[0056] The cross-member 124 is contoured to define a central recess 135.A rotatable “barn door” latching member 137 is positioned within therecess 135 and is movable between an extended position with the latchingmember 137 extending downwardly from the cross-member 124 intointerfering relation with a top edge 139 of a meal tray 140, and aretracted position with the latching member 137 extending laterally toone side within the recess 135 in non-interfering relation with the topedge 139 of the meal tray 140. The meal tray 140 also includes a recess141 which communicates with the top edge 139 of the meal tray 140. Therecess 135 in the cross-member 124 and the recess 141 in the meal tray140 collectively form a recess within which the latching member 137resides, and thus prevents inadvertent impact from passing passengerswhich could cause deployment of the meal tray 140.

[0057] The locking pins 125, 126 are manually operable bydownwardly-extending fingers 125A, 126 from the lower side of thecross-member 124 when the meal tray 140 is in its deployed position.

[0058] Installation is accomplished without tools. Repairs and partreplacement may be made without tools and without removing the dresscover from the seat back 25.

Meal Tray Assembly—Alternative Embodiment

[0059] Referring now to FIGS. 17, 18 and 19, an alternative embodimentmeal tray assembly 150 is shown. A meal tray 151 is mounted for movementbetween a stowage position flush against the back side of a seat backpan 25A, FIG. 19, and a lowered, horizontal use position, FIG. 18. Anelongate latch access port 153 extends through the meal tray 151 nearits top edge. Note that the latch access port is “subflush” to thebottom surface of the meal tray 151, and is surrounded by a recess 154.

[0060] A latch mounting plate 155 is secured to the back side of theseat back pan 25A, to which is mounted an annular detent plate 157.Detent plate 157 includes four 90 degree detent dimples 157A molded intothe face. An elongate latch 160 is carried by the detent plate 157 by apin assembly 158 and is rotatable between a release position, shown inFIG. 18, where the elongate latch 160 may be aligned with and extendedthrough the elongate latch access port 153 for permitting movement ofthe meal tray 151 to and from the stowage position and the use position.When the meal tray 151 has been moved to the stowage position with thelatch 160 extending though the latch access port 153, the latch 160 isrotated in either the clockwise or counterclockwise direction 90degrees. The latch 160 overlaps the edge of the latch access port 153and is caught on the edge of the meal tray 151 surrounding the latchaccess port 153, locking the meal tray 151 in the stowage position.

[0061] To release the meal tray 151 and allow it to be moved to the useposition, the latch 160 is rotated a further 90 degrees in eitherdirection and into alignment with the lengthwise axis of the latchaccess port 153. In this position, the meal tray 151 may be lowered pastthe latch 160 and into the use position.

[0062] Because the latch 160 captures the meal tray 151 through thelatch access port 153, inadvertent disengagement of the meal tray 151 byforce applied in any direction is prevented, in contrast with current“barn door” latches. In addition, the recess 154 around the latch accessport 153 prevents inadvertent rotation of the latch 160 and deploymentof the meal tray 151 to the use position, as might otherwise occur whena passenger brushes against the tray while moving to or from his or herown seat.

[0063] A passenger seat, passenger seat leg module and a method ofconstructing a passenger seat are described above. Various details ofthe invention may be changed without departing from its scope.Furthermore, the foregoing description of the preferred embodiment ofthe invention and the best mode for practicing the invention areprovided for the purpose of illustration only and not for the purpose oflimitation—the invention being defined by the claims.

I claim:
 1. A passenger seat, comprising: (a) a seat bottom chassisincluding a plurality of leg modules, said leg modules for beingattached to fixed, spaced-apart attachment points on a supportingsurface; (b) a plurality of beam elements for being carried by said legmodules; (c) a plurality of clamp joints for being positioned on a firstside of said leg modules in a first laterally-offset relation thereto ina first spaced-apart relation to the attachment points of the supportingsurface and for receiving the plurality of beam elements for defining aladder frame assembly having a first specified width and seat spacing;and (d) said plurality of clamp joints being removable from the firstside of said leg modules and positioned on a second, opposite side ofsaid leg modules in a second laterally-offset relation thereto fordefining a ladder frame assembly having a second specified width andseat spacing while the plurality of leg modules maintain the sameposition relative to each other and thus to the fixed, spaced apartattachment points whereby the location of the seats may be altered whileusing the same beam elements.
 2. A passenger seat according to claim 1,and including a seat back recline assembly, comprising: (a) a pluralityof seat section assembly modules carried by said leg modules, and a seatback unit pivotally-mounted between two of the section assembly modulesfor permitting the angle of the seat back relative to the seat bottomchassis to be varied as desired by the passenger; and (b) a recline unitfor controlling movement of the seat back and locking the seat back in adesired recline position.
 3. A passenger seat according to claim 1,wherein each of said leg modules comprises: (a) a rear foot block andfloor tie assembly; (b) a front leg: (c) a diagonal leg tie connectingthe rear foot block and the front leg; (d) wherein a first one of theplurality of clamp joints is connected in laterally-offset relation toone side of the diagonal leg tie intermediate the rear foot block andthe front leg; and (e) wherein a second one of the plurality of clampjoints is connected in laterally-offset relation to one side of thefront leg.
 4. A passenger seat according to claim 1 or 3, wherein saidclamp joint comprises an attachment element for being attached to theleg module and an annular collar element for receiving a beamtherethrough.
 5. A passenger seat according to claim 4, wherein saidclamp joint attachment element includes holes therein for receivingattachment bolts therethrough and through mating holes in the legmodule.
 6. A passenger seat according to claim 4, wherein said clampjoint collar includes: (a) an axially-extending split therein forallowing the collar to be spread sufficiently to receive the beamtherethrough; and (b) a threaded fastener adjustably connecting thecollar on opposite sides of the split for permitting the collar to betightened for locking the beam in place within the collar in apredetermined position and loosened for permitting the beam to theremoved from or shifted axially within the collar.
 7. A passenger seataccording to claim 1, wherein said passenger seat includes first andsecond spaced-apart leg modules and further wherein: (a) the clampjoints of the first leg module are positioned on a left side thereof;and (b) the clamp joints of the second leg module are positioned on aright side thereof.
 8. A passenger seat according to claim 1, whereinsaid passenger seat includes first and second spaced-apart leg modulesand further wherein: (a) the clamp joints of the first leg module arepositioned on a right side thereof; and (b) the clamp joints of thesecond leg module are positioned on a right side thereof.
 9. A passengerseat according to claim 1, wherein said passenger seat includes firstand second spaced-apart leg modules and further wherein: (a) the clampjoints of the first leg module are positioned on a left side thereof;and (b) the clamp joints of the second leg module are positioned on aleft side thereof.
 10. A passenger seat leg module, comprising: (a) arear foot block and floor tie assembly; (b) a front leg; (c) a diagonalleg tie connecting the rear foot block and the front leg; (d) a firstclamp joint for being connected in laterally-offset relation to aselected one of a left or right side of the diagonal leg tieintermediate the rear foot block and the front leg for receiving a beamtherethrough; and (e) a second clamp joint for being connected inlaterally-offset relation to a selected one of a left or right side ofthe front leg for receiving a beam therethrough.
 11. A passenger seatleg module according to claim 10, wherein said clamp joint comprises anattachment element for being attached to the leg module and an annularcollar element for receiving the beam therethrough.
 12. A passenger seatleg module according to claim 11, wherein said clamp joint attachmentelement includes holes therein for receiving attachment bolts therethrough and through mating holes in the leg module.
 13. A passenger seatleg module according to claim 1 2, wherein said clamp joint collarincludes: (a) an axially-extending split therein for allowing the collarto be spread sufficiently to receive the beam thereth rough; and (b) athreaded fastener adjustably connecting the collar on opposite sides ofthe split for permitting the collar to be tightened for locking the beamin place within the collar in a predetermined position and loosened forpermitting the beam to the removed from or shifted axially within thecollar.
 14. A method of mounting a passenger seat to attachment pointson a supporting surface, comprising the steps of: (a) providing: (i) aseat bottom chassis including a plurality of leg modules, said legmodules for being attached to fixed, spaced-apart attachment points on asupporting surface; (ii) a plurality of beam elements for being carriedby said leg modules; (iii) a plurality of clamp joints; (b) positioninga clamp joint to each of the plurality of leg modules for clamping theplurality of leg modules together in spaced-apart relation to eachother, each said clamp joint having a hole therethrough for receiving abeam element; (c) extending the plurality of beam elements through anopening in the clamp joints for defining a ladder frame assembly havinga predetermined width and seat spacing.
 15. A method according to claim14, and including the steps of: (a) removing the beams from the clampjoints; (b) removing the clamp joints from one side of the leg modulesand attaching the clamp joints to an opposite side of the leg modules;(c) extending the plurality of beam elements through respective openingsin the clamp joints to define a ladder frame assembly having a secondspecified width and seat spacing.
 16. A method according to claim 15 andincluding the steps of: (a) positioning the clamp joints of a first legmodule on a left side thereof; and (b) positioning the clamp joints of asecond leg module on a right side thereof.
 17. A method according toclaim 15 and including the steps of: (a) positioning the clamp joints ofa first leg module on a right side thereof; and (b) positioning theclamp joints of a second leg module on a right side thereof.
 18. Amethod according to claim 15 and including the steps of: (a) positioningthe clamp joints of a first leg module on a left side thereof; and (b)positioning the clamp joints of a second leg module on a left sidethereof.